For the first time, a new study shows that birds exposed to AM waveband interference lose their way.

Researchers at the University of Oldenburg in Germany published a study in the coming issue of Nature, proving that the magnetic compass of robins fail when exposed to even the slightest AM radio waveband electromagnetic interference that are found in all urban areas.

Previously, it was believed that below a certain threshold value, what is known as "electrosmog" or man-made electromagnetic noise, had no impact on nature or biological processes.

This new study led by Prof. Dr. Henrik Mountsen, however, shows that a signal of even a thousandth of the limit value is enough to throw the birds off and make them lose their sense of direction and navigation. The level of electrosmog involved can be found everywhere in any urban environment.

The effects of electrosmog on birds are much less in rural environments, even in areas just one or two kilometres outside a major city's limits.

The researchers cooperated with Prof. Dr. Peter J. Hore of Oxford University in conducting the 7-year long research. Together, they found that although the level of interference required wouldn't come from just electrical lines or mobile phone networks, it would be generated by use of any electronic device.

It has been widely known that migratory birds use the Earth's magnetic field to navigate and determine their migratory direction, some birds flying thousands of miles across continents.

The research started when Mountsen's team were testing the robin bird's navigational abilities by placing them in wooden huts. They found that in the testing area, the birds were absolutely lost, until they covered the huts in aluminium. The aluminium wouldn't interfere with the Earth's magnetic field in any way, but would block out any "electrosmog" around.

To confirm the results, Mountsen had his doctorate students conduct multiple "double-blind" test where several generations of students were unknowingly engaged in performing the same tests. This was done to conclusively prove the results were the same every time without bias.

The study shows the disruptive electrosmog was generated by a much broader frequency and much lower intensity than previous studies had suggested, far below the limits set by the World Health Organization and the International Commission on Non-Ionizing Radiation Protection.

As a result, Mountsen expressed concern on the future survival of migratory birds, as well as the potential effects of electrosmog on human beings, which he said have yet to be investigated.

Nature magazine considered the story important enough that it will be on the covers when the issue is released on May 15.